Foster shares two purification processes from Saint John of the Cross that occur during the dark night of the soul. The first "involves stripping us of dependence upon exterior results." I read this and thought of the old hymn "and the things of earth will grow strangely dim..." In our desperation, the external things which seemed to matter so much start to fall away. They're no help to us, no comfort in the dark. Foster says we become "less in control of our own destiny." We can't pray and say we trust God, but then make it happen on our own (and I love how people then give God all the glory). Foster personalizes this purification by saying "For me the greatest value in my lack of control was the intimate and ultimate awareness that I could not manage God. God refused to jump when I said, 'Jump!' Neither by theological acumen not by religious technique could I conquer God. God was, in fact, to conquer me."
The second purification of Saint John of the Cross "involves stripping us of dependence upon interior results." This is when we begin to doubt what we were once so sure of. God has a way of shaking the foundations of our identity so that nothing but what the Holy Spirit has built will remain. Foster says "We are led to a profound and holy distrust of all superficial drives and human striving. We know more deeply than ever before our capacity for infinite self-deception."
I want to encourage you again to hold fast during these times. Keep praying and talking to God even when no response comes. He is purifying us and desires to perfect us according to his image.